A NAND flash memory is known as a kind of a nonvolatile semiconductor memory device. A storage device incorporating the NAND flash memory is also known.
When accessing the NAND flash memory in the storage device based on a logical address supplied from a host to the storage device, an address conversion table showing the correspondence between the logical address and a data storage position in the NAND flash memory is used. This address conversion table includes elements capable of accessing the whole area of the NAND flash memory. Therefore, the amount of management information increases as the memory capacity of the NAND flash memory increases, and the memory capacity of a RAM required to store the address conversion table also increases.